What constitutes HER2 Positive

knowledgeforpower

My path reports from a biopsy say Her2+ no amplification.  Does this mean I am Her2 positive?

mattscot

There is an indication that the tumor may be but that is not definitive.  I think this is based on your biopsy results versus pathology after surgery- right?  The pathology after surgery will be more definitive.  There are several tests performed to determine HER2 status.  Did they perform ICH on the sample ?-- that is the first test that is performed if it is equivocal which is ICH 2 then they perform the FISH which is considered HER+ with a score of 2.2 or higher.  The Oncotype DX now tests for HER2 status as well which tests based on RNA analysis.

In my situation -  the biopsy on my invasive tumor tested as HER-, the pathology after surgery came back ICH 2 equivocal, the FISH 2.3 considered positive (one point above).  I then had the Oncotype DX which came back negative.   My doctor believes that I am HER- but I did go forward with chemo and herceptin.

Hope this is helpful.

Lories

Hi mattscot - thanks for your reply - I too am awaiting FISH and Oncotype results and so you really explained it well.  I kept wondering what the score threshold was, but was not sure how to even ask.  I will hopefully hear tomorrow from my oncologist since the nurse told me the test results are in.

I also appreciate that you decided to do Herceptin.  I am curious though, are you doing chemo because of the size of your tumor or the stage?  I am wondering since your nodes were clear. I am still trying to learn all this stuff.  thanks again.  Lori

mattscot

My doctor strongly wanted me to do the chemo plus Herceptin. 2nd opinion echoed this  -- At first AC recommended then after I got the oncotype score - it was changed to  Taxtotere/cytoxin.  I was advised that Herceptin would be effective in a borderline or negative situation. However I believe this is a grey zone --- there are no studies in the adjuvant setting to back this up .  There are studies in the metastisis setting in which the benefit of Herceptin in the HER2negative or borderline cases - was questioned.  Because my oncotype dx score 16 was lowish (certainly lower than I had anticiipated with the HER2 issue)--- that without the HER2 issue I may  have  declined chemo.  As to size of tumor my doctor did raise this as a factor but lobular invasive tumors tend to be larger .  

Let us know How it goes with the FISH and Oncotype

  

Roxy3

Her2 must be over-expressed at +++ to be considered officially her2+ positive. You may want to visit the fact sheet phamplets from Genetech website tol officially verify this for you.